Occurrence of copper resistant mutants in the toxic cyanobacteria Microcystis aeruginosa: characterisation and future implications in the use of copper sulphate as algaecide

Abstract Grazing of zooplankton on phytoplankton may contribute to a reduction of harmful cyanobacteria in eutrophic waters. However, the feeding capacity and interaction between zooplankton and toxic cyanobacteria vary among grazer species. In this study, laboratory feeding experiments were designed to measure the grazing rate of the copepod Cyclops vicinus on Microcystis aeruginosa and the potential microcystin (MC) accumulation in the grazer. Copepods were fed a mixed diet of the edible green alga Ankistrodesmus falcatus and toxic M. aeruginosa for 10 days. The results showed that C. vicinus efficiently ingested toxic Microcystis cells with high grazing rates, varying during the feeding period (68.9–606.3 Microcystis cells animal-1 d-1) along with Microcystis cell density. Microcystis cells exhibited a remarkable induction in MC production under grazing conditions with concentrations 1.67–12.5 times higher than those in control cultures. Furthermore, C. vicinus was found to accumulate MCs in its body with concentrations increasing during the experiment (0.05–3.21 μg MC animal-1). Further in situ studies are needed to investigate the ability of Cyclops and other copepods to assimilate and detoxify MCs at environmentally relevant concentrations before deciding on the biocontrol of Microcystis blooms by copepods.

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Demographic responses of selected rotifers (Rotifera) and cladocerans (Cladocera) fed toxic Microcystis aeruginosa (Cyanobacteria)

Fundamental and Applied Limnology / Archiv für Hydrobiologie ◽

10.1127/fal/2020/1285 ◽

2020 ◽

Vol 193 (3) ◽

pp. 261-274

Author(s):

Alfredo Pérez-Morales ◽

S.S.S. Sarma ◽

S. Nandini ◽

Cristian Alberto Espinosa-Rodríguez ◽

Ligia Rivera-De la Parra

Keyword(s):

Population Growth ◽

Life Table ◽

Microcystis Aeruginosa ◽

Green Algae ◽

Somatic Growth ◽

Phytoplankton Species ◽

Scenedesmus Acutus ◽

Cladoceran Species ◽

Toxic Cyanobacteria ◽

Demographic Responses

Tropical waterbodies contain several species of toxic cyanobacteria including Microcystis, which adversely affect the somatic growth, survival and fecundity of zooplankton. Scenedesmus, one of the most common green algae, is even found in Microcystis -dominated waterbodies. It is, therefore possible that in natural ponds, rotifers and cladocerans feed on mixed phytoplankton species containing algae and cyanobacteria. In this work, we quantified demographic responses of three rotifer species (Brachionus calyciflorus, B. rubens, and Plationus patulus), and three cladoceran species (Simocephalus mixtus, Daphnia cf. mendotae and Moina macrocopa) fed toxic Microcystis aeruginosa only or mixed with Scenedesmus acutus. The highest population growth for both rotifer and cladoceran species was observed when Scenedesmus was offered alone or at 75 % of the diet. Daphnia cf. mendotae and B. rubens were less affected by Microcystis while M. macrocopa and B. calyciflorus were more adversely influenced, which was also corroborated by life table demography. In competition bioassays, D. cf. mendotae was more efficient, alone or in competition, when fed with 50 or 25 % of Microcystis. This work explains the dynamics of the zooplanktonic community against gradual changes in phytoplankton due to the presence of cyanobacteria.

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Moroccan actinobacteria with promising activity against toxic cyanobacteria Microcystis aeruginosa

Environmental Science and Pollution Research ◽

10.1007/s11356-020-10439-2 ◽

2020 ◽

Vol 28 (1) ◽

pp. 235-245

Author(s):

Soukaina El Amrani Zerrifi ◽

El Mahdi Redouane ◽

Richard Mugani ◽

Inês Ribeiro ◽

Maria de Fátima Carvalho ◽

...

Keyword(s):

Microcystis Aeruginosa ◽

Toxic Cyanobacteria

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Responses of the rotifer Brachionus calyciflorus to two tropical toxic cyanobacteria (Cylindrospermopsis raciborskii and Microcystis aeruginosa) in pure and mixed diets with green algae

Journal of Plankton Research ◽

10.1093/plankt/fbq042 ◽

2010 ◽

Vol 32 (7) ◽

pp. 999-1008 ◽

Cited By ~ 40

Author(s):

M. C. S. Soares ◽

M. Lurling ◽

V. L. M. Huszar

Keyword(s):

Microcystis Aeruginosa ◽

Green Algae ◽

Brachionus Calyciflorus ◽

Cylindrospermopsis Raciborskii ◽

Toxic Cyanobacteria ◽

Rotifer Brachionus Calyciflorus

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SIZE EFFECT OF COPPER NANOPARTICALS ON MICROCYSTIS AERUGINOSA

Vietnam Journal of Biotechnology ◽

10.15625/1811-4989/16/2/13449 ◽

2018 ◽

Vol 16 (2) ◽

pp. 361-367

Author(s):

Nguyen Trung Kien ◽

Tran Thi Thu Huong ◽

Nguyen Hoai Chau ◽

Dang Dinh Kim ◽

Duong Thi Thuy

Keyword(s):

Particle Size ◽

Microcystis Aeruginosa ◽

Copper Nanoparticles ◽

Algal Blooms ◽

Water Environment ◽

Freshwater Ecosystems ◽

Particle Sizes ◽

Toxic Cyanobacteria ◽

The Stability ◽

Effect Of Copper

Cyanobacterial and toxins produced in cyanobacterial water blooms cause serious environmental problems which effects on freshwater ecosystems. The use of nanomaterials to control algal blooms is a new potential way for practical application due to its antibacterial as well as distinct physicochemical properties of nanomaterials. The particle size is one of the most determinant characteristics creating the different between nanomaterials and their larger bulk counterparts. However, size-dependent toxicity of nanoparticles has remained largely unknown. This study aimed to evaluate effect of three different nanoparticle sizes (d ≤ 10 nm; 30 nm ≤ d ≤ 40 nm and d ≥ 50 nm) on toxic cyanobacteria Microcystis aeruginosa. The copper nanoparticles were synthesized by electrochemical method and coated with chitosan to enhance the stability of materials in the water environment. The copper nanoparticle concentrations selected for toxic test were range from 0 (control); 0,01ppm; 0,05ppm; 0,1 ppm; 1ppm and 5 ppm. After ten days of experiment, the growth of M. aeruginosa was mainly affected at concentrations of 1 ppm and 5 ppm and there are no differences in inhibition between the particle sizes with efficiency of more than 80% in comparison to control. The highest toxicity of copper nanoparticles in M. aeruginosa was observed at particle size of 30 nm ≤ d ≤ 40 nm with EC50 = 0,73 ppm, which was respectively three to seven times less than the particle sizes of d ≥ 50 nm (EC50 = 2,62 ppm) and d ≤ 10nm (EC50 = 5,02 ppm) at the same time.

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Filter Feeding and Carbon and Nitrogen Assimilation of a Freshwater Bivalve (Unio douglasiae) on a Toxic Cyanobacterium (Microcystis aeruginosa)

Applied Sciences ◽

10.3390/app11199294 ◽

2021 ◽

Vol 11 (19) ◽

pp. 9294

Author(s):

Soon-Jin Hwang ◽

Yun-Ju Lee ◽

Min-Seob Kim ◽

Baik-Ho Kim

Keyword(s):

Microcystis Aeruginosa ◽

Nitrogen Assimilation ◽

Clearance Rates ◽

Freshwater Bivalve ◽

Filter Feeder ◽

Dual Isotope ◽

Carbon And Nitrogen ◽

Isotope Tracers ◽

Toxic Cyanobacteria ◽

Flowing System

We investigated the possible intake of toxic cyanobacteria (Microcystis aeruginosa) as a nutrient resource for a filter-feeder bivalve (Unio douglasiae) based on the measurement of feeding and assimilation rates of carbon and nitrogen in a limited space with no current for 72 h using 13C and 15N dual isotope tracers. With high clearance rates, the unionid rapidly removed Microcystis cells within 24 h, but only a small amount of carbon and nitrogen were incorporated into the tissues. Even with the low assimilation rates, the mussels showed more favorable uptake of carbon than of nitrogen from toxic Microcystis water, and of tissues, the gills and gut accumulated more carbon and nitrogen than the muscle and mantle. Collectively, our findings indicate that although Unio douglasiae effectively uptake toxic Microcystis cells, they can assimilate only low amounts of nutrients into tissues within three days, despite a non-flowing system.

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Combined treatment of toxic cyanobacteria Microcystis aeruginosa with hydrogen peroxide and microcystin biodegradation agents results in quick toxins elimination

Acta Biochimica Polonica ◽

10.18388/abp.2017_2538 ◽

2018 ◽

Vol 65 (1) ◽

pp. 133-140 ◽

Cited By ~ 7

Author(s):

Dariusz Dziga ◽

Anna Maksylewicz ◽

Magdalena Maroszek ◽

Sylwia Marek

Keyword(s):

Hydrogen Peroxide ◽

Secondary Metabolites ◽

Microcystis Aeruginosa ◽

Combined Treatment ◽

Cell Lysis ◽

Water Reservoirs ◽

Promising Alternative ◽

Toxic Cyanobacteria ◽

Algicidal Compounds

In some conditions the growth of toxic cyanobacteria must be controlled by treatment with algicidal compounds. Hydrogen peroxide has been proposed as an efficient and relatively safe chemical which can remove cyanobacteria from the environment selectively, without affecting other microorganisms. However, the uncontrolled release of secondary metabolites, including toxins may occur after such a treatment. Our proposal presented in this paper is fast biodegradation of microcystin released after cell lysis induced by hydrogen peroxide. The effectiveness of both Sphingomonas sp. and heterologously expressed MlrA enzyme in the removal of the toxin from Microcystis aeruginosa culture has been investigated. The results indicate that neither Sphingomonas cells nor MlrA are affected by hydrogen peroxide in the concentrations which stop the growth of cyanobacteria. A several-fold microcystin reduction was documented in the presence of these agents with biodegradation ability. Our results provide evidence that such a combined treatment of water reservoirs dominated by microcystin-producing cyanobacteria may be a promising alternative which allows fast elimination of toxins from the environment.

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Genotyping and functional regression trees reveals environmental preferences of toxic cyanobacteria (Microcystis aeruginosa complex) along a wide spatial gradient

10.1101/2019.12.20.885111 ◽

2019 ◽

Author(s):

Gabriela Martínez de la Escalera ◽

Angel M. Segura ◽

Carla Kruk ◽

Badih Ghattas ◽

Claudia Piccini

Keyword(s):

Microcystis Aeruginosa ◽

Environmental Conditions ◽

Regression Trees ◽

Spatial Gradient ◽

Functional Regression ◽

Environmental Preferences ◽

Temperature Conductivity ◽

Toxic Cyanobacteria ◽

Melting Analysis

AbstractAddressing ecological and evolutionary processes explaining biodiversity patterns is essential to identify the mechanisms driving community assembly. In the case of bacteria, the formation of new ecologically distinct populations or ecotypes is proposed as one of the main drivers of diversification. New ecotypes arise when mutation in key functional genes or acquisition of new metabolic pathways by horizontal gene transfer allow the population to exploit new resources, making possible their coexistence with parental population. Recently, we have reported the presence of toxic, microcystin-producing organisms from the Microcystis aeruginosa complex (MAC) through a wide environmental gradient (800 km) in South America, ranging from freshwater to estuarine-marine waters. In order to explain this finding, we hypothesize that the success of toxic organisms of MAC in such array of environmental conditions is due to the existence of ecotypes having different environmental preferences. So, we analysed the genetic diversity of microcystin-producing populations of Microcystis aeruginosa complex (MAC) by qPCR and high resolution melting analysis (HRMA) of a functional gene (mcyJ, involved in microcystin synthesis) and explored its relationship with the environmental conditions through the gradient by functional classification and regression trees (fCART). Six groups of mcyJ genotypes were distinguished and selected by different combinations of water temperature, conductivity and turbidity, determining the environmental preferences of each group. Since these groups were based on the basis of similar sequence and ecological characteristics they were defined as ecotypes of toxic MAC. Taking into account that the role of microcystins in MAC biology and ecology has not yet been elucidated, we propose that the toxin might have a role in MAC fitness that would be mainly controlled by the physical environment in a way such that the ecotypes that thrive in the riverine zone of the gradient would be more stable and less influenced by salinity fluctuations than those living at the marine limit of the estuary. These would periodically disappear or being eliminated by salinity increases, depending on the estuary dynamics. Thus, ecotypes generation would be an important mechanism allowing toxic MAC adapting to and succeed in a wide array of environmental conditions.

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